Datasheet

149
AT89C51ID2
4289C–8051–11/05
AC Testing Input/Output
Waveforms
AC inputs during testing are driven at V
CC
- 0.5 for a logic “1” and 0.45V for a logic “0”.
Timing measurement are made at V
IH
min for a logic “1” and V
IL
max for a logic “0”.
Float Waveforms
For timing purposes as port pin is no longer floating when a 100 mV change from load
voltage occurs and begins to float when a 100 mV change from the loaded V
OH
/V
OL
level
occurs. I
OL
/I
OH
≥ ± 20 mA.
Clock Waveforms Valid in normal clock mode. In X2 mode XTAL2 must be changed to XTAL2/2.
INPUT/OUTPUT
0.2 V
CC
+ 0.9
0.2 V
CC
- 0.1
V
CC
-0.5V
0.45V
FLOAT
V
OH
- 0.1V
V
OL
+ 0.1V
V
LOAD
V
LOAD
+ 0.1V
V
LOAD
- 0.1V